TPR Study of Core-Shell Fe@Fe<sub>3</sub>O<sub>4</sub> Nanoparticles Supported on Activated Carbon and Carbon Nanotubes

Abstract

Core-shell nanoparticles Fe@Fe<sub>3</sub>O<sub>4</sub> supported on activated carbon (AC) and carbon nanotubes (CNTs) have been studied by H<sub>2</sub> temperature-programmed reduction (TPR). Nanoparticles with size of 6.5 nm were synthesized by iron(II) oleate thermal decomposition and were supported on activated carbon and carbon nanotubes by colloid deposition method. The nanoparticles Fe@Fe<sub>3</sub>O<sub>4</sub> are characterized by TEM and IR. Reduction of nanoparticles on AC starts at 140?C, whereas reduction of nanoparticles on CNTs starts at 200?C. Moreover, gasification of CNTs with methane releasing starts at 450?C, whereas gasification of AC is negligible at temperatures up to 800?C. All these findings illustrate a strong difference in the interaction between nanoparticles and the support material for AC and CNTs

SYNTHESIS, CHARACTERIZATION AND ELECTROCHEMICAL PERFORMANCE OF ACTIVATED CARBON SUPPORTED MnO2 FOR ELECTROCHEMICAL CAPACITOR

“…3. RH-AC is stable up to 500 o C and the small peak at 550 o C is attributed to the methanation of carbon (C + H 2 → CH 4 ) [12]. All the MnAC samples show three well-distinct peaks, corresponding to the reduction steps of MnO 2 .…”

Combination of immobilized TiO2 and zero valent iron for efficient arsenic removal in aqueous solutions

“…Conversely, a complex reduction profile was obtained for nZVI (Figure 5). The profile was split into three individual peaks centered at around 325 C, 530 C, and 730 C, that can be related to the H 2 consumption corresponding to the stepwise reduction of iron oxides, typically γ-Fe 2 O 3 (maghemite), Fe 3 O 4 (magnetite), and FeO (wüstite), respectively, to yield Fe 0 (metallic iron) (Ryu et al, 2008;Bychko, 2012). Since the intensity of each reduction peak is significantly different, it can be inferred the presence of mainly magnetite with wüstite to a lesser extent and a small amount of maghemite all of which, according to the TEM micrographs, would be located on the external surface of nZVI.…”

Synthesis and Electrochemical Evaluation of Carbon Supported Pt-Co Bimetallic Catalysts Prepared by Electroless Deposition and Modified Charge Enhanced Dry Impregnation

“…This reduction temperature agrees well with Co oxide reduction observed by others for carbon-supported cobalt [25,26] and was chosen as the temperature for bulk reduction of Co oxide. The small, broad shoulder between 500-600˝C can be associated with Co 0 -assisted hydrogenation of the carbon support to methane [27,28]. This temperature region should be avoided to minimize alteration of the support surface; thus, reduction temperatures for all compositions were limited to 400˝C.…”